I stuck a new 4.2 engine in my 1997 Ford Van (same engine as a lot of the F150 pickups) about two months ago. The engine runs great but I've got a squeak that is driving me insane and has been for the last 5000 miles.

I realize there is also a van section of the forum but it gets less that 1/8 the traffic this part of the forums get. Since it's the same engine I thought I'd get a quicker response here.

Anyway, I'm pretty sure its one of the engine pulleys but I have no idea which one. I've tried two different brand belts with no luck.
My first belt was a cheap Napa belt the second one was the most expensive they sold at Autozone with some BS life time warranty.

I've already tried belt dressing on the cheap Napa belt. It would quiet the squeak for about a minute and then resume it's obnoxious high pitched wail.

I can probably rule out the alternator, it's brand new as are the belt tensioner pulley, and the lower idler pulley.

The Lower Idler Pulley Napa Sold me seems to be smaller in diameter and made of plastic. When they handed it to me I said "Do you promise this will work" and they said yes. What's your opinion of Plastic pulleys? Could a brand new one squeak? Should I get rid of it and go with the OEM Motorcraft version?

If anyone else is looking for 4.2 idler pulleys I believe the OEM pulleys are YS315 Bottom Serpentine Pulley and YS316 Top Smooth Pulley the best prices I found for new ones were at RockAuto. com for about $25.00 each

This leaves the upper idler pulley, AC pulley, Power Steering Pulley, Water Pump Pulley and Crankshaft Pulley.

I tried a three foot piece of garden hose to try to listen for the squeak but no matter where I stuck it in the engine it sounded about the same.


Any suggestions would be greatly appreciated. I'm leaving in a week for a 2000 mile road trip and the only other solution I have is too turn up the stereo so loud that I can't hear the squeak.

I don't know if it makes any difference but the Squeak is just as bad if not worse at speeds above 40mph. It also squeaks at idle.

 

im not sure why pulleys would squeek. the first thing i do it , with the motor running, setting in the drive way, spray laundry soap and water on the inside of the belt and see if the noise changes. IF it does, the problem is the belt or pulley grooves. Since you have a new belt, maybe you have oil on the pulleys. Soapy water will help clean them up and tell you if that is the problem. TO check the compressore, you can put ont he defrost or AC and after it engages, see if the noise changes.

 

Also...if you have the room...use the "broomstick method" CAREFULLY place the end of a broomstick on a suspected area,and put your ear to the broomstick.Usually you will get a noise transfer,and it will help pinpoint the issue.Normally I would use a mechanics stethescope,but most folks dont have access to one.....they DO however have access to the broomstick!

 

Just ordered a mechanics stethoscope earlier today. Will try the soap tomorrow afternoon.

 

I would also replace the belt tensioner itself not just the pulley, and the other idler pulley. I do believe that the idler/tensioner pulleys are interchangeable if you do buy the tensioner assembly.

 

"I would also replace the belt tensioner" - already did.

 

when you changed the pulleys, did you change the bearings as well? Also, after looking at pic(very good move), could it be alternator bearings or brushes? Alternator will make wierd squealing noise when at max output too, just a thot.

 

It turned out to be a lot simpler than I thought it would be. All it needed was a good cleaning. I washed the belt in warm water and dish soap and I cleaned all the pulleys with brake cleaner. To my amazement the squeak disappeared and has been gone 200 miles so far. It's hard to believe I lived with it squeaking for 5000 miles when all it needed was a bath.

 

yep, been there, done that. congrats on a cheap fix.